How to add image watermark in PowerPoint document in C#

Spire.Presentation offer developers an easy way to add the watermarks to the presentation slides. There are two kinds of watermarks in PowerPoint documents: text watermark and image watermark. We'll learn how to add image watermark in PowerPoint document via Spire.Presentation.

The goal of the article is to make an image as a background img watermark as following screenshot.

Here comes to the steps of how to add image watermarks in C#:

Step 1: Create a presentation document and load the document from the file

Presentation ppt = new Presentation();
ppt.LoadFromFile(fileName);

Step 2: Get the image you want to add as image watermark.

IImageData image = ppt.Images.Append(Image.FromFile("Header.png"));

Step 3: Set the properties of SlideBackground, and then fill the image as watermark.

ppt.Slides[0].SlideBackground.Type = Spire.Presentation.Drawing.BackgroundType.Custom;
ppt.Slides[0].SlideBackground.Fill.FillType = FillFormatType.Picture;
ppt.Slides[0].SlideBackground.Fill.PictureFill.FillType=PictureFillType.Stretch;
ppt.Slides[0].SlideBackground.Fill.PictureFill.Picture.EmbedImage = image;

step4: Save the document to a new file.

ppt.SaveToFile(resultFileName, Spire.Presentation.FileFormat.PPT);

Full codes:

using Spire.Presentation;
using Spire.Presentation.Drawing;
using System.Drawing;
namespace AddimageWatermark
{

    class Program
    {

        static void Main(string[] args)
        {
            Presentation ppt = new Presentation();
            ppt.LoadFromFile(fileName);
            IImageData image = ppt.Images.Append(Image.FromFile("Header.png"));
            ppt.Slides[0].SlideBackground.Type = Spire.Presentation.Drawing.BackgroundType.Custom;
            ppt.Slides[0].SlideBackground.Fill.FillType = FillFormatType.Picture;
            ppt.Slides[0].SlideBackground.Fill.PictureFill.FillType = PictureFillType.Stretch;
            ppt.Slides[0].SlideBackground.Fill.PictureFill.Picture.EmbedImage = image;

            if (fileExtensions == ".ppt")
            {
                ppt.SaveToFile(resultFileName, Spire.Presentation.FileFormat.PPT);
            }
            else
            {
                ppt.SaveToFile(resultFileName, Spire.Presentation.FileFormat.Pptx2007);
            }

            Viewer(resultFileName);
        }
    }
}

How to add image watermark in PowerPoint document in C#

See Also